Philippa Christie was classmates with Joe throughout school, but it was only when they were cast in the leading roles of their school's version of Grease that they became firm friends.

The 18-year-old had already won the part of Sandy in the Harton Technology College's production when she sat in on Joe's audition for the role of Danny.

The art and design student, from Westoe, said: "No one knew Joe could sing at all. When I heard him, I was gobsmacked. It was the talk of the school.

"From there, he was just fantastic and I've been to see him lots of times.

"We had to spend quite a lot of time together rehearsing and grew really close."

Joe got the part as Danny and the pair recorded some of the show's songs together.

Philippa, who is travelling to London this weekend to watch the show, is delighted Joe is living the dream.

But she's been getting a bit of attention as a result of their friendship.

"The show's just getting bigger and bigger, and he's met so many celebrities. Friends and family are always asking me how Joe's getting on.

"He's just doing so well. Every week he seems to sound better and better. He can pull anything off.

"I'm so proud of him, but it's so scary to think he's famous now and things will never be the same."

After Sunday's shock sing-off between Lucie Jones and twins John and Edward, which saw the Welsh teen leave, Philippa admits anyone could be next.

She added: "It's worrying. Joe must be feeling like a lot of good people have left and he could be in the bottom.

"Hopefully the judges wouldn't vote him off, but the way Simon is going, I just don't know."